using __deepcopy__ on custom object in python?

Question

I am a writing a custom `Queue` class that uses `list` as a composite attribute. I do not sublcass from list. my code is here. I get the error for deepcopy which I have pasted below. can someone help me about what I is going wrong? Thanks ``` from iterator import Iterator class Abstractstruc(object): def __init__(self): assert False def __str__(self): return "<%s: %s>" %(self.__class__.__name__,self.container) class Queue(Abstractstruc,Iterator): def __init__(self,value=[]): self.container=[] self.size=0 self.concat(value) def add(self, data): self.container.append(data) def remove(self): self.container.pop(0) def peek(self): return self.container[0] def __getitem__(self,index): return self.container[index] def __iter__(self): return Iterator(self.container) def concat(self,value): for i in value: self.add(i) def __bool__(self): return len(self.container)>0 def __len__(self): return len(self.container) def __deepcopy__(self,memo): return Queue(copy.deepcopy(self.container,memo)) if __…

Accepted Answer

You need to import the `copy` module:

```
import copy
```

The error message:

```
Traceback (most recent call last):
  File "test.py", line 56, in <module>
    q4=copy.deepcopy(q3)
NameError: name 'copy' is not defined
```

`NameError` is raised when Python does not know what the bare name `copy` refers to.

using deepcopy on custom object in python?

Solution

Problem